The present invention relates generally to peristaltic pumps and more specifically to clamping mechanisms for use on ophthalmic surgical equipment fluidic cassettes.
Most prior art peristaltic pumps work by compressing or squeezing a length of flexible tubing (sometimes between a fixed race) using a rotating roller head. As the roller head rotates, the rollers pinch off a portion of the tubing and push any fluid trapped in the tubing between the rollers in the direction of rotation. Peristaltic pumps are widely used in medical applications because of their predictable, constant flow properties. These prior art systems, however, typically require manual connection of the pump tube segment around the rotating roller head.
Another prior art pump is disclosed in U.S. Pat. No. 6,293,926 B1 (Sorensen, et al.) which describes a peristaltic pump having a molded flow channel contained on an elastomeric sheet that is bonded or mechanically attached to a rigid substrate. The pump head rollers are mounted radially from the axis of rotation of the pump motor and compress the elastomeric flow channels against the rigid substrate. In order to fully compress the flow channels against the rigid substrate, and thereby maximize the efficiency of the pumping system, the cassette must be held tightly against the pump rollers. The cassette, on the other hand, must also be easy to install on and be removed from the surgical console. One cassette latching mechanism, disclosed in U.S. Patent Publication No. 20030202894 (Leukanech, et al.), discloses a cassette latching mechanism having a motor that rotates a latching wheel, producing cam-like movement of a pair of latching arms and thereby pivoting the latching rails to a fully closed and locked position holding the cassette. The DC servo motors used in this device are expensive and can be relatively abrupt in operation.
Accordingly, a need continues to exist for an inexpensive cassette clamping having smooth, controlled movement.